In recent years SCUs have emerged as planned environments for persons with dementing illness. At present, SCUs are not well described, the differences between self-designated SCUs and non-designated units are not clearly drawn, and the need for or utility of SCUs has not been demonstrated empirically. SCUs are thought to use a combination of specialized environmental, programmatic and staff development strategies; however, this assertion may or may not be supported empirically. Previous research has not developed adequate methods for measuring SCU attributes nor for classifying these settings. This study develops and tests an empirical typology for designated SCUs and non-designated units in the State of Minnesota. An exploratory analysis of all 446 nursing homes in Minnesota is used to evaluate outcomes based on this empirical typology for SCU classification. MANOVA calculations are used to test the effects of unit type on a variety of outcomes. The study develops and tests a psychoeducational intervention in 20 units (stratified by type). Interrupted time series and repeated measures analysis of variance techniques are used to test the impact of the intervention on resident staff, and family outcomes. SCUs in the state are assessed longitudinally over a four-year period to document change on these units relative to the intervention. New instruments are developed and tested to collect primary data on the impact of SCUS.